Abstract:
In a method of corrosion protection of rebar in concrete the sacrificial anode is held in place by wrapping a first wire around a first rebar portion and a second wire at second rebar portion and twisting together the first and second free ends to tension the wrappings. This can be used either on two separate rebars which are parallel or at right angles or can be used at longitudinally spaced positions on a single rebar where the rebar roughening prevents the two wrappings from sliding as the wires are tensioned by the twisting. In many cases a covering material such as a porous mortar is cast onto the outer surface of the anode and in this case the mortar and the wire are located such that the wire exits from the sacrificial anode at a position separate from the layer of covering material.
Abstract:
A single anode system used in multiple electrochemical treatments to control steel corrosion in concrete comprises a sacrificial metal that is capable of supporting high impressed anode current densities with an impressed current anode connection detail and a porous embedding material containing an electrolyte. Initially current is driven from the sacrificial metal [1] to the steel [10] using a power source [5] converting oxygen and water [14] into hydroxyl ions [15] on the steel and drawing chloride ions [16] into the porous material [2] around the anode such that corroding sites are moved from the steel to the anode restoring steel passivity and activating the anode. Cathodic prevention is then applied. This is preferably sacrificial cathodic prevention that is applied by disconnecting the power source and connecting the activated sacrificial anode directly to the steel.
Abstract:
A method of protecting steel in a reinforced concrete element is disclosed. The reinforced concrete of the element contains an electrolyte. The method involves providing a primary anode, which is a sacrificial anode, and providing a secondary anode, which is connected to a positive terminal of at least one source of direct current, ‘DC’, power. The primary anode and secondary anode are arranged to have an ionic connection with the steel in the reinforced concrete element via the electrolyte. The primary anode is connected to the steel in the reinforced concrete element using an electron conductor. The negative terminal of the source of DC power is connected to the steel in the reinforced concrete element using an electron conductor.
Abstract:
A hybrid sacrificial galvanic anode, an anodic system including the hybrid sacrificial anode, and a method of cathodically protecting steel reinforcement in concrete structures is provided. The hybrid anode provides initial steel polarization followed by long term galvanic protection without the use of batteries or external power supplies.
Abstract:
Disclosed is an adhesive hydrogel containing a polymer matrix, water, and a polyhydric alcohol, wherein the polymer matrix contains a copolymer of a monofunctional monomer with a single polymerizable C-C double bond and a polyfunctional monomer with two or more polymerizable C-C double bonds, the monofunctional monomer contains a nonionic (meth)acrylamide-based monomer, and the polyfunctional monomer has a composition formula: C l H m O n , where O is an oxygen atom in an ether bond, l is an integer greater than or equal to 4, m is an integer greater than or equal to 6, and n is an integer greater than or equal to 0.
Abstract:
A sacrificial anode assembly for cathodically protecting and/or passivating a metal section, comprising: (a) a cell, which has an anode and a cathode arranged so as to not be in electronic contact with each other but so as to be in ionic contact with each other such that current can flow between the anode and the cathode; (b) a connector attached to the anode of the cell for electrically connecting the anode to the metal section to be cathodically protected; and (c) a sacrificial anode electrically connected in series with the cathode of the cell; wherein the cell is otherwise isolated from the environment such that current can only flow into and out of the cell via the sacrificial anode and the connector. The invention also provides a method of cathodically protecting metal in which such a sacrificial anode assembly is cathodically attached to the metal via the connector of the assembly, and a reinforced concrete structure wherein some or all of the reinforcement is cathodically protected by such a method.
Abstract:
The invention relates to a hydraulic binding agent, comprising K, Ca, aluminosilicates and optionally Li, Na, and MG, characterized in that it comprises the following constituents: a) latent hydraulic aluminosilicate glass at a ratio of (CaO+MgO+AI 2 O 3 )/SiO 2 > 1 and b) alkali activator of the empirical formula (I): a(M 2 O) * X(SiO 2 ) * y(H 2 O), where M = Li, Na, K, a = 0-4 and x = 0-5 and y = 3-20, wherein the mol ratio Ca/Si 0.1. The invention further relates to binding agent matrixes, to mortar, to concrete adhesive and to metal anodes produced from said binding agent.
Abstract:
An anode for use in cathodic protection of steel in concrete is formed from an electrically conductive material such as zinc and an ionically conductive material which is preferably a humectant and/or has a pH greater than 12 to enhance current flow. The materials are intimately intermixed through at least a part of the anode body and compressed into the anode body with an electrical connecting lead formed into a core of the body which is wholly conductive material. Portions of the electrically conductive material are pressed into electrical contact to form a plurality of electrically conductive paths within the anode body. Many of the voids in the body are interconnected to form a plurality of ionically conductive paths through the anode body by causing the humectant to migrate through the voids. The large surface area between the ionically conductive paths and the electrically conductive paths increase significantly the contact surface area of the anode body to increase current flow.